Which design feature distinguishes wide-body from narrow-body?

• A. Longer Wings
• B. More Seats
• C. Twin Engines
• D. Two Aisles

Answer: (D)

Two aisles in the cabin are what distinguish wide-body from narrow-body aircraft. A wider fuselage lets designers place two parallel aisles, creating three seating blocks across the width and enabling larger capacity and different seating layouts. Narrow-body aircraft use a single central aisle because the cabin isn’t wide enough for two aisles. So the number of aisles is the clearest design feature that separates the two types. While wings, seat counts, or engine counts can vary independently, they don’t define the basic category in the same way.